882 research outputs found
Ambipolar Field Effect in Topological Insulator Nanoplates of (BixSb1-x)2Te3
Topological insulators represent a new state of quantum matter attractive to
both fundamental physics and technological applications such as spintronics and
quantum information processing. In a topological insulator, the bulk energy gap
is traversed by spin-momentum locked surface states forming an odd number of
surface bands that possesses unique electronic properties. However, transport
measurements have often been dominated by residual bulk carriers from crystal
defects or environmental doping which mask the topological surface
contribution. Here we demonstrate (BixSb1-x)2Te3 as a tunable topological
insulator system to manipulate bulk conductivity by varying the Bi/Sb
composition ratio. (BixSb1-x)2Te3 ternary compounds are confirmed as
topological insulators for the entire composition range by angle resolved
photoemission spectroscopy (ARPES) measurements and ab initio calculations.
Additionally, we observe a clear ambipolar gating effect similar to that
observed in graphene using nanoplates of (BixSb1-x)2Te3 in
field-effect-transistor (FET) devices. The manipulation of carrier type and
concentration in topological insulator nanostructures demonstrated in this
study paves the way for implementation of topological insulators in
nanoelectronics and spintronics.Comment: 7 pages, 4 figure
The All-Data-Based Evolutionary Hypothesis of Ciliated Protists with a Revised Classification of the Phylum Ciliophora (Eukaryota, Alveolata)
This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ The file attached is the published version of the article
A local outbreak of dengue caused by an imported case in Dongguan China
<p>Abstract</p> <p>Background</p> <p>Dengue, a mosquito-borne febrile viral disease, is found in tropical and sub-tropical regions around the world. Since the first occurrence of dengue was confirmed in Guangdong, China in 1978, dengue outbreaks have been reported sequentially in different provinces in South China transmitted by<sup>.</sup>peridomestic <it>Ae. albopictus </it>mosquitoes, diplaying <it>Ae. aegypti</it>, a fully domestic vector that transmits dengue worldwide. Rapid and uncontrolled urbanization is a characteristic change in developing countries, which impacts greatly on vector habitat, human lifestyle and transmission dynamics on dengue epidemics. In September 2010, an outbreak of dengue was detected in Dongguan, a city in Guangdong province characterized by its fast urbanization. An investigation was initiated to identify the cause, to describe the epidemical characteristics of the outbreak, and to implement control measures to stop the outbreak. This is the first report of dengue outbreak in Dongguan, even though dengue cases were documented before in this city.</p> <p>Methods</p> <p>Epidemiological data were obtained from local Center of Disease Control and prevention (CDC). Laboratory tests such as real-time Reverse Transcription Polymerase Chain Reaction (RT-PCR), the virus cDNA sequencing, and Enzyme-Linked immunosorbent assay (ELISA) were employed to identify the virus infection and molecular phylogenetic analysis was performed with MEGA5. The febrile cases were reported every day by the fever surveillance system. Vector control measures including insecticidal fogging and elimination of habitats of <it>Ae. albopictus </it>were used to control the dengue outbreak.</p> <p>Results</p> <p>The epidemiological studies results showed that this dengue outbreak was initiated by an imported case from Southeast Asia. The outbreak was characterized by 31 cases reported with an attack rate of 50.63 out of a population of 100,000. <it>Ae. albopictus </it>was the only vector species responsible for the outbreak. The virus cDNA sequencing analysis showed that the virus responsible for the outbreak was Dengue Virus serotype-1 (DENV-1).</p> <p>Conclusions</p> <p>Several characterized points of urbanization contributed to this outbreak of dengue in Dongguan: the residents are highly concentrated; the residents' life habits helped to form the habitats of <it>Ae. albopictus </it>and contributed to the high Breteau Index; the self-constructed houses lacks of mosquito prevention facilities. This report has reaffirmed the importance of a surveillance system for infectious diseases control and aroused the awareness of an imported case causing the epidemic of an infectious disease in urbanized region.</p
Repertoire Enhancement with Adoptively Transferred Female Lymphocytes Controls the Growth of Pre-Implanted Murine Prostate Cancer
In prostate cancer, genes encoding androgen-regulated, Y-chromosome-encoded, and tissue-specific antigens may all be overexpressed. In the adult male host, however, most high affinity T cells targeting these potential tumor rejection antigens will be removed during negative selection. In contrast, the female mature T-cell repertoire should contain abundant precursors capable of recognizing these classes of prostate cancer antigens and mediating effective anti-tumor immune responses.We find that syngeneic TRAMP-C2 prostatic adenocarcinoma cells are spontaneously rejected in female hosts. Adoptive transfer of naĂŻve female lymphocytes to irradiated male hosts bearing pre-implanted TRAMP-C2 tumor cells slows tumor growth and mediates tumor rejection in some animals. The success of this adoptive transfer was dependent on the transfer of female CD4 T cells and independent of the presence of CD25-expressing regulatory T cells in the transferred lymphocytes. We identify in female CD4 T cells stimulated with TRAMP-C2 a dominant MHC II-restricted response to the Y-chromosome antigen DBY. Furthermore, CD8 T cell responses in female lymphocytes to the immunodominant MHC I-restricted antigen SPAS-1 are markedly increased compared to male mice. Finally, we find no exacerbation of graft-versus-host disease in either syngeneic or minor-antigen mismatched allogeneic lymphocyte adoptive transfer models by using female into male versus male into male cells.This study shows that adoptively transferred female lymphocytes, particularly CD4 T cells, can control the outgrowth of pre-implanted prostatic adenocarcinoma cells. This approach does not significantly worsen graft-versus-host responses suggesting it may be viable in the clinic. Further, enhancing the available immune repertoire with female-derived T cells may provide an excellent pool of prostate cancer reactive T cells for further augmentation by combination with either vaccination or immune regulatory blockade strategies
Steroids in the Treatment of IgA Nephropathy to the Improvement of Renal Survival: A Systematic Review and Meta-Analysis
Studies have shown that steroids can improve kidney survival and decrease the risk of proteinuria in patients with Immunoglobulin A nephropathy, but the overall benefit of steroids in the treatment of Immunoglobulin A nephropathy remains controversial. The aim of this study was to evaluate the benefits and risks of steroids for renal survival in adults with Immunoglobulin A nephropathy.We searched the Cochrane Renal Group Specialized Register, Cochrane Controlled Trial Registry, MEDLINE and EMBASE databases. All eligible studies were measuring at least one of the following outcomes: end-stage renal failure, doubling of serum creatinine and urinary protein excretion. Fifteen relevant trials (nâ=â1542) that met our inclusion criteria were identified. In a pooled analysis, steroid therapy was associated with statistically significant reduction of the risk in end-stage renal failure (RR: 0.46, 95% CI: 0.27 to 0.79), doubling of serum creatinine (RRâ=â0.34, 95%CIâ=â0.15 to 0.77) and reduced urinary protein excretion (MDâ=ââ0.47g/day, 95%CIâ=ââ0.64 to â0.31).We identified that steroid therapy was associated with a decrease of proteinuria and with a statistically significant reduction of the risk in end-stage renal failure. Moreover, subgroup analysis also suggested that long-term steroid therapy had a higher efficiency than standard and short term therapy
Search for Kaluza-Klein Graviton Emission in Collisions at TeV using the Missing Energy Signature
We report on a search for direct Kaluza-Klein graviton production in a data
sample of 84 of \ppb collisions at = 1.8 TeV, recorded
by the Collider Detector at Fermilab. We investigate the final state of large
missing transverse energy and one or two high energy jets. We compare the data
with the predictions from a -dimensional Kaluza-Klein scenario in which
gravity becomes strong at the TeV scale. At 95% confidence level (C.L.) for
=2, 4, and 6 we exclude an effective Planck scale below 1.0, 0.77, and 0.71
TeV, respectively.Comment: Submitted to PRL, 7 pages 4 figures/Revision includes 5 figure
Measurement of the average time-integrated mixing probability of b-flavored hadrons produced at the Tevatron
We have measured the number of like-sign (LS) and opposite-sign (OS) lepton
pairs arising from double semileptonic decays of and -hadrons,
pair-produced at the Fermilab Tevatron collider. The data samples were
collected with the Collider Detector at Fermilab (CDF) during the 1992-1995
collider run by triggering on the existence of and candidates
in an event. The observed ratio of LS to OS dileptons leads to a measurement of
the average time-integrated mixing probability of all produced -flavored
hadrons which decay weakly, (stat.)
(syst.), that is significantly larger than the world average .Comment: 47 pages, 10 figures, 15 tables Submitted to Phys. Rev.
Pilot Scale Production of Highly Efficacious and Stable Enterovirus 71 Vaccine Candidates
BACKGROUND: Enterovirus 71 (EV71) has caused several epidemics of hand, foot and mouth diseases (HFMD) in Asia and now is being recognized as an important neurotropic virus. Effective medications and prophylactic vaccine against EV71 infection are urgently needed. Based on the success of inactivated poliovirus vaccine, a prototype chemically inactivated EV71 vaccine candidate has been developed and currently in human phase 1 clinical trial. PRINCIPAL FINDING: In this report, we present the development of a serum-free cell-based EV71 vaccine. The optimization at each step of the manufacturing process was investigated, characterized and quantified. In the up-stream process development, different commercially available cell culture media either containing serum or serum-free was screened for cell growth and virus yield using the roller-bottle technology. VP-SFM serum-free medium was selected based on the Vero cell growth profile and EV71 virus production. After the up-stream processes (virus harvest, diafiltration and concentration), a combination of gel-filtration liquid chromatography and/or sucrose-gradient ultracentrifugation down-stream purification processes were investigated at a pilot scale of 40 liters each. Although the combination of chromatography and sucrose-gradient ultracentrifugation produced extremely pure EV71 infectious virus particles, the overall yield of vaccine was 7-10% as determined by a VP2-based quantitative ELISA. Using chromatography as the downstream purification, the virus yield was 30-43%. To retain the integrity of virus neutralization epitopes and the stability of the vaccine product, the best virus inactivation was found to be 0.025% formalin-treatment at 37 °C for 3 to 6 days. Furthermore, the formalin-inactivated virion vaccine candidate was found to be stable for >18 months at 4 °C and a microgram of viral proteins formulated with alum adjuvant could induce strong virus-neutralizing antibody responses in mice, rats, rabbits, and non-human primates. CONCLUSION: These results provide valuable information supporting the current cell-based serum-free EV71 vaccine candidate going into human Phase I clinical trials
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
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